As a way to find the missing information in experiments, static
quantum chemical calculations, like density functional theory (DFT),
have been used to aid the interpretation of mass spectra by revealing
possible structures and mapping out the reaction network during
fragmentation. Such a method has been successfully applied in
understanding the reaction pathways for H and H\(_2\)  losses during PAH
fragmentation [1]}, [2]}, [3]}. An evident
weakness of this static approach is the lack of information about the
mass distribution of the investigated fragments. This can be overcome
within the Rice-Ramsperger-Kassel-Marcus theory [4]}, [5]}, using DFT calculated transition state energies. However, a prior knowledge about
fragmentation channels is needed (which is often unknown) and the
dynamical process during fragmentation cannot be probed. Another
challenge is to interpret the pathways leading to larger mass losses
than H\(_2\)  due to the more complex rearrangements of chemical bonds.
For H\(_2\)  loss, it is feasible to enumerate all possible routes of
H\(_2\)  formation and calculate reaction barriers for each pathway using
DFT. In principle, this can also be done for C\(_{2n}\) H\(_x\) 
loss [6]}, but requires so many trials and the use of chemical intuition
which might not cover all possible fragmentation pathways.
Experimental evidence for the molecular structures formed upon fragmentation
is therefore urgently needed.
